Tire building apparatus



/July 12, 1938 A. L. vHl-:sToN 2,123,586

TIRE `BUILDING APPARATUS Filed Aug. 2a, 1956 5 sheets-sheet 1 -7f/'( l 4i f/ l &1 ff i 4 I I/ 5 9 -Z/ /9 V22 z/ 5 MM l ` INVENTOR ALLE/v L.l-/EsTa/v yj A ATTORNEY July 12, 1938. A. l.. HEs-roN 1235536 TIREBUILD'ING APPARATUS y Filed Aug. 28;'1956 5 Sheets-Sheet 2 ATTORNEY July12, 1938'. A. L. HEs'roN i 5 2,123,586

i TIR BUILDING APPARATUS Filed Aug. 28, v19:56 5 sheets-sheet 3 z l i7115 i if I l 4 7 C I 57 9i. J7 j Z 4' /Z ma faz i197 "9 J INVNTOR ALLEN L.HESTo/v i-il 1 ATTO RNEY July 12,l 1938. A. L. HEsTN TIE BUILDINGAPPARATUS Filed Aug. 2s; v193s 5 Sheets-Sheet 4 Patented July 12, 1938UNITED STATES PATENT O'FFIQE 2,123,586 TIRE BUILDING APPARATUS Allen L.Heston, Akron, Ohio, assignor to National Rubber Machinery Company,

ratus, and more especially it relates to tire building apparatuscomprising collapsible, sectional forms or drums used in the fabricationof pneumatic tire casings having relatively large crosssectional areaand relatively small rim or bead diameter and to associated mechanismfor collapsing the drums and for manipulating the collapsed sectionsthereof.

Because of the small bead diameter of the tires mentioned, it isnecessary for the sections of the collapsible forms to have the greatestcollapsing movement obtainable, and to this end it has been proposed tcprovide a collapsible, sectional drum having key sections that aremovable axially,

when collapsed, out of the tire and out of the normal plane of the drumto allow for maximum collapsing movement of the intermediate drumsections., Such constructions as heretofore provided have included aslidable spindle on the tire building machine for supporting thecollapsed key sections, and collapsing of the latter has been effectedmanually while the drum was stationary.

The chief objects of this invention are to provide an improvedcollapsible tire building drum wherein the key sections, after beingcollapsed, may be removed entirely away from the drum and tire buildingmachine; to provide means whereby the collapsing of key sections andintermediate sections of the drum is effected by means of the power thatrotates the drum; and to provide for obtaining the greatest possiblecollapsing movement of the drum sections. Other objects will be manifestas the specification proceeds.

Of the accompanying drawings:

Fig. 1 is a side elevation of apparatus embodying the invention in itspreferred form, showing the key sections of the drum in collapsedposition and removed from the normal plane of the drum, parts beingbroken away and in section for clearness of illustration;

Fig. 2 is a' section on the line 2-2 of Fig. 1, showing the device foreffecting collapse of the key sections of the drum disassociated fromthe latter;

Fig. 3 is a front elevation of the improved tire building drum in itsexpanded, operative condition;

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a vertical section through the drum, as viewed from line 5-5of Fig. 3, including a portion of device used for collapsing the keysections;

Fig. 6 is a longitudinal section through the Akron, Ohio, a

1936, Serial No. 98,291

outer end portion of the key sections, including a placed over saidstructure built upon the drum;

Fig. 7 is a front elevati axial structure of the shield or guard that iswhile a tire is being on of the improved drum showing the key sectionsthereof in collapsed condition;

Fig. 8 is a section Fig. 9 is a sectional intermediate sections dition,as seen from the Referring to the machine of the usual o of which l l isa power d jecting therefrom and upon said spindle, there drawings,

on the line 8-8 of Fig. 5; and view of the drum, with the thereof incollapsed conline 9--9 of Fig. l.

lil is a tire building r preferred construction riven rotary spindleprol2 is a sleeve mounted being a bushing I3, Fig.

l, mounted between the spindle and sleeve adjacent the inner end of thelatter. The sleeve i2 is arranged to rotate with the spindle, aspresently will be explained, rotate relatively thereto. spindle andsleeve is effe venting rotation of the and, upon occasion, to Relativerotation of the cted by retarding or presleeve while the spindlecontinues to rotate, and to this end the inner end of the sleeve is prbrake drum I4. Engageable with l5 that is operated by means internalbrake band of a hand lever I6.

ovided with an integral the latter is an Mounted upon the outer end ofspindle ll is a collapsible tire building ing three key sections form ordrum comprisgenerally designated i8,

i8 and three intermediate sections generally dessaid sections consistsof I9, the latter being of somewhat key sections. Each of an arcuatedrum portion proper 20 and a pair of flange members 2 l, 2l

mounted upon the outer periphery thereof. The

outer periphery of each drum portion 2b is formed with a longitudinallyextending, central rib 22 of the same height as the thickness and theadjacent lateral margins of flanges 2 I,

of the the latter abut said rib when the flanges are arranged for thebuilding est width. The flanges of Vtire casings of narrow- 2l may beadjustable laterally for the manufacture of tires of wider width, as iswell known i At their outer lateral curve radially inwardly, ripheralmargin formed tending groove 24. ed, operative condition,

side of the drum are endless and n the art.

margins the flanges 2l and each has its inner pewith a longitudinallyex- When the drum is in expandthe grooves 24 on each each receives thecomplementally-shaped outer peripheral portion of respectivecollapsible, articulated trimming rings 25, 25, Figs.

3 and 4. As shown in Fig. 3, each trimming ring 25 consists of threesections that are hinged together at two points 2S, 26. At a third pointthe end sections of the ring meet at a beveled junction 21. The ring 25is expanded so as to seat in a groove 24 by means of a manually operatedlatch 28 that is pivotally mounted at 2S on one ring section adjacentthe free end thereof and is engageable with a stud Sil mounted upon theadjacent ring section on the opposite side of the junction 21. Whenmounted in place as shown in Figs, 3 and 4, the rings 25 constituteradially inward extensions of the drum flanges 2I, and tire casingsbuilt upon the drum have their bead portions built against said rings,as indicated by the broken line profile of a tire shown in Fig. 4. Therings 25 are removed from the drum before the latter is collapsed toremove a tire therefrom. The provision of the said rings makes itpossible to collapse the drum sections to a greater extent thanotherwise would be possible.

As previously stated, the building drum is mounted upon the outer endportion of spindle II, and to this end a portion of the latter disposedwithin sleeve I2 is of reduced diameter, as shown at I Ia, Fig. 5, andmounted upon said reduced portion and keyed thereto is a hub structure32 for the intermediate drum sections I9. The hub structure 32 carries acircumscribing collar or bushing 33, Fig. 5, upon which the outer end ofthe sleeve I2 is journaled. Forwardly of reduced portion IIa, thespindle II is of still further reduced diameter, said reduced portionbeing designated IIb and being formed with a slightly tapered terminalportion or nose.

Formed integral with the hub structure 32 and extending axiallyforwardly therefrom are three overhanging bracket members 35, 35, whichmembers are symmetrically arranged about spindle portion IIband spacedoutwardly therefrom. Each bracket member 35 is formed with two parallelradial bores that are spaced apart axially of the drum, and slidablymounted in the said bores are respective tubular bushings 36, the innerends of which have outwardly extending flanges that engage the bracketstructure to limit radially outward movement of said bushings in saidbores. Slidably mounted for axial movement in each bushing 36 is atubular sleeve 31, the outer end of which is fixedly connected to thedrum portion 20 of an intermediate drum section I 9, Adjacent its innerend, each sle-eve 31 is formed interiorly with a circumferential flange38 through which extends a headed rod 39, the head of which slidesfreely within the sleeve and is adapted to engage the flange 38 uponoccasion for a purpose presently to be explained. The rod 39 has asliding fit with the flange 38 and projects a substantial distancebeyond the inner end of the sleeve 31 where its end is threaded into aflanged cap or fixture 40 that is permanently secured, as by welding, ina shallow counter-bore in the inner end of bushing 36. The structuresdescribed constitute radial supports and guides for the intermediatedrum sections I9. When the latter are in their collapsed position, asshown in Fig. 9, the rods 39 are completely telescoped with the sleeves31, the latter are in engagement with the rod-caps 40, and the caps 40and the inner ends of bushings 36 are in abutting relation with spindleend IIb. Thus the spindle end limits the inward, collapsing movement ofthe drum sections I9, and because of its reduced diameter, it permitsmaximum collapsing movement of said sections. Because of the sectional,telescopic character of the drum-section supports, adequate support forthe drum sections is provided when the latter are in operative, expandedposition. Engagement of the flanged ends of bushings 36 with the bracketstructures 35 provides means for limiting the outward movement of thedrum sections, and the feature of threading the rods 39 into the caps 49provides for adjusting the length of the rods whereby the properexpanded positioning of the intermediate drum sections accurately andeasily is achieved.

The collapsing diate drum sections I9 are effected by power means, andto this end a ring gear 42 is keyed to the outer end of the sleeve I2,and meshed with said gear are three symmetrically disposed pinions 43,43 that are mounted upon one end of respective shafts 44, the latterbeing parallel to the axis of the drum and to each other. As is mostclearly shown in Fig. 8, each shaft 44 is journaled in axially spacedapart bearing structures 35a, 35a formed on one of the brackets 35, andbetween the said bearing structures, in the medial plane of the drum,each shaft 44 is provided with a pinion 46. The pinions 45 mesh withrespective racks 41, the outer ends of which are pivotally connected, at48, to the drum portions 20 of the respective intermediate sections I9.Each pinion 4S and rack 41 are retained in meshed relation by means of ayoke or guide 49 that is swiveled upon the shaft 44 on each side of saidpinion. Each bracket 35 is suitably cut away, as is most clearly shownin Fig. 9, to permit of angular movement of said yoke during theexpanding and collapsing of the intermediate drum sections.

Collapsing of the intermediate drum sections I9 is effected duringintervals in which the key sections of the drum are removed. To collapsethe intermediate drum sections, the spindle II is driven so as to rotatethe drum sections in the direction indicated by the arrow in Fig. 9, thesleeve I2 and gear 42 thereon rotating with said spindle for the reasonthat centrifugal force urging the drum sections outwardly is suicient tocounteract any tendency of the pinions 43 to move relatively of saidgear 42. When the sections are rotating as described, application ofbrake I5 Yto brake drum I4 on sleeve I2 slows down or stops the latter,causing gears 43 to move in the manner of planetary gears about gear 42and thereby to be rotated and thus to rotate their shafts 44 and pinions46 thereon. This moves the racks 41 and drum sections I9 connectedthereto inwardly, which inward movement continues until the rod caps 40engage reduced portion IIbI of the spindle II. The drum sections I9 areexpanded by driving the spindle I I in the opposite direction andapplying the brake to the sleeve I2 in the manner described. The brakeis applied gently so that it may be immediately released when the drumsections attain the positions desired. Engagement of the inner ends ofbushings 3B with the bracket structures 35 determines the outward limitof movement of the sections.

The key sections of the drum are a separate unit that may be completelyremoved from the drum to facilitate the collapsing of the intermediatesections and the removal of a finished tire casing therefrom. The keysection unit comprises an axially disposed, hollow, elongate screwmember 5l, and mounted Within one end thereof is an axial tubularbushing 52, Fig. 5, that is receivable upon the reduced portion IIb ofand expanding of the intermespindle I I. The screw I is of such lengthas to extend forwardly of the plane of the drum a substantial distance,and at its forward end the interior of the screw is locally formed withhexagonal walls, the same y,constituting a socket. 53 for the receptionof a collapsing tool or member subsequently to be described. The majorportion of the screw 5I, from its forward end rearwardly, is exteriorlythreaded as shown, its rear end portion being of slightly reduceddiameter and unthreaded and having a bearing bushing 54 mounted thereon.Journaled upon the bushing 5 is a hub structure 55 for the key sections,said hub structure being retained against axial movement by a thrustwasher 55 on one side thereof and a flange 5'I on the bushing 513 on theother side thereof. A washer 58 is positioned between the thrust washer53 and the major threads on the screw, and a nut 59 threaded onto theinner end of screw structure 5I retains the assembly on the latter. Thehub structure 55 is formed with three radially extending bracketstructures G0, 5B that overhang the hub fore and aft, and in theassembled, operative condition of the drum are in intercalated relationto brackets 35 of hub 32 of the intermediate drum sections. At its innerend, between two of the brackets 6U, the hub 55 is formed with aradially projecting lug 6! that is engageable in a forwardly opening,axially extending groove 62 formed in one of the brackets 35 of hub 32,as is most clearly shovvn in Figs. 5 and 9. The arrangement is such asto assure accurate registry of hubs 55 and 32 and provides adequateinterlocking of the hubs so that hub 55 will be rotated by hub 32 whenthe latter is driven.

Each bracket structure e@ is formed with two parallel, spaced apart,radial bores in which are mounted respective tubular bushings te, thelatter being disposed in the same plane as the bushings 35 of the otherhub 32 in the assembled condition of the drum. The bushings 54 projectoutwardly beyond the brackets 55, and slidably mounted in each of saidbushings is a heavy rod or spindle 55, the outer end of which is securedin a boss 66 formed on the inner peripheral face oi drum porti-on 20 ofa key section I8. There are two rods 55 for each key section, said rodsguiding the latter in their collapsing and expanding movements. Becauseof their shorter length, the key sections do not require to be collapsedto the same extent as the intermediate sections in order that they willbe positioned inwardly of the bead diameter of a tire casing built uponthe drum, said bead diameter being indicated by a broken line circle inFig. 7. Collapsing movement of the key sections is limited by thebushings 5d, the outer ends of which are engaged by the bosses 55 of thekey sections when the latter are completely collapsed. The outward,expanding movement of the key sections is limited by the expandingmechanism presently to be described and by hooks 6l mounted at therespective ends of the key sections and engageable with suitable studsor pins 53 mounted at opposite ends of the intermediate sections.

Mechanism for expanding and collapsing the key sections i8 comprises apair of bell cranks l5, 'l5 for each key section, the respective bellcranks of each pair being pivotally mounted at their elbows uponrespective pivot pins 'I'I projecting laterally from opposite sides ofeach bracket 60, near the front end of the latter. One arm of each bellcrank extends obliquely rearwardly toward the axis of the drum, and theother arm extends obliquely rearwardly and radially outwardly in thedirection of the drum sections. The free ends of thel latter arms ofeach pair of bell cranks are pivotally connected to one end ofrespective links 12, the other ends of said links being pivotallyconnected to opposite ends of a pivot pin 'I3 that is mounted in afixture 'Id that is secured to the inner periphery of drum portion 25 ofa key section IB, centrally thereof.

For rocking said bell cranks 1G, a nut I5 is threaded onto the threadportion of screw 5I, forwardly of hub 55 thereon, said nut being formedwith three, symmetrically arranged, radially extending ears TI.Projecting laterally from opposite sides of the respective ears 'I1 areheaded or flanged studs 18, 'I8 that engage in respective longitudinallyextending slots 'I9 formed in the free ends of the radially inwardlyextending arms of bell cranks 1B.

The arrangement is such that axial movement of the nut I6 toward thefront end of screw 5I will effect collapse of the key sections I8 to theposition shown in Fig. 7. Reverse travel of the nut "I5 will expand thesections to operative position in circumferential alignment withintermediate sections I9. When the drum is in opera'- tive, expandedcondition and rotating, all of the elements previously described,including screw 5I, will rotate about the axis of the drum because ofthe interengagement of said elements. The screw 5i, however, may berestrained or held against rotation, and when so held, relative angunlar movement between said screw and the rotating nut 'l5 will cause thelatter to travel longitudinally of the screw to collapse or expand thekey sections. Thus the key sections are collapsed or expanded by powerfrom the spindle I I.

The mechanism for restraining rotation of the screw 5I is combined withapparatus for moving the key section assembly, after collapse, out ofthe plane of the drum and to a point sufficiently remote to permit atire to be removed from the drum simply by removing it off the collapsedintermediate drum sections I9. Said apparatus is shown in Fig. 1,wherein 82 is an overhead track rail, 83 is a carriage suspended fromwheels 84 that ride on said track rail, 85 is a connection pivotallysuspended from said carriage, 85 is a reversely curved hanger rodextending downwardly from said connection, and 81 is a cylindrical hubi'lxedly mounted on the lower end of said rod 86. The hanger rod 85 isvertically adjustable in the connection 85 so that the axis of hub B'Imay be aligned with the axis of the drum, and the track rail 82 isdisposed parallel to the axis of the drum, at least in the regionthereof that is disposed directly above the drum and adjacent thereto.

Axially journaled in the hub 81 is a spindle 89, and mounted uponopposite ends of the hub are caps 90, SI, respectively, to which saidspindle is keyed, there being thrust washers 92 positionedV between thehub and the respective caps. The spindle projects from the hub at theend thereof nearest the drum, the projecting portion of the spindlecomprising a cylindrical terminal portion 89a having a tapered nose andadapted to fit within the cylindrical portion of the bore of screw 5I,and a hexagonal portion 8gb receivable within the hexagonal socketformed in the forward end of said screw 5I. The hexagonal portion 89h ofthe spindle constitutes a shoulder that abuts cap SI, and the hub andspindle are retained in assembled relation by a nut 93 that is threadedonto the spindle and abuts cap 90.

The latter is of larger diameter than the hub, and in its radiallyprojecting portion is formed with a bushed aperture. An angular fixture94 is secured to the hub 81 with a portion of its structure formed witha bushed aperture that is aligned with the similar aperture in cap 90. Ahardened steel shear pin 95 is mounted in said aligned apertures, thearrangement being such that said pin will be sheared oil. if torque inthe spindle 89 is excessive.

In order to protect the operator of the machine from accidental contactwith that portion of the screw 5| that projects forwardly beyond thedrum, a removable guard is provided, which guard is mounted upon thescrew during the building of a tire and removed therefrom before thedrum is collapsed to remove the tire. Said guard comprises a hollowcylindrical structure 91, Fig. 6, having a closed outer end and havingits inner end of such size as to t over the cylindrical forward end ofnut 16 and formed with bayonet slots, such as the slot 98, forengagement with respective studs 99 projecting radially from said hub.Within the cylinder is a compression spring |00 positioned between theclosed end of the cylinder and a generally cylindrical seat |0I. Thelatter is formed with a countersunk recess |02 that closely ts the endof the screw 5| when the structure is mounted thereon. A stud |03extends through cylinder 91 and is engageable with a marginal portion ofseat |0| for retaining the latter in the cylinder. When the guard ismount ed upon the screw 5|, the spring |00 serves to effectsui'liciently firm engagement of the bayonet slot 98 and studs 99 assecurely to retain the guard in place while the drum is rotating, yetpermitting quick and easy removal of the guard when desired.

In the operation of the apparatus, let it be assumed that the drum is inthe expanded, operative condition shown in Fig. 3, that the trimmingrings 25 are in place as shown, and that the guard 91 is mounted uponthe forward end of the screw 5| as shown in Fig. 6. The spindle is thendriven to rotate the drum and the sleeve I2, and a tire casing isfabricated upon the drum in any known or preferred manner. Thecross-section of the tire is indicated in broken lines in Fig. 4 to showthe position of the inside diameter of the tire with relation to thetrimming rings 25 and the smaller diameter of the drum flanges 2|. Whenthe building of the tire casing is completed, rotation of the drum isstopped, the guard 91 is removed from the front end of screw 5|, and thetrimming rings 25 are collapsed and removed from the drum. Then themobile apparatus that comprises the spindle 89 is moved into place andsaid spindle is inserted into the axial opening of screw 5| so thathexagonal portion 89h of said spindle engages in the complementallyshaped socket 53 of the saidY screw, as shown in Fig. 5.

While the screw 5| is held stationary by the spindle 89, rotation of thedrum is resumed, the direction of rotation being such that relativemovement of the screw 5| and nut 16 causes the latter to move axiallytoward the forward end of the screw. This produces angular movement ofthe several pairs of bell cranks 10, with which the nut is engaged, anddraws the key sections I8 radially inwardly until such inward movementis stopped by engagement of the bosses B6 with the upper ends ofbushings 64. Rotation ofthe drum is stopped as soon as this condition isreached. The position of the 'key sections in collapsed position isshown in Fig. 7, the broken line `circle outside said key sectionsindicating the smallest diameter of the tire casing. Since the hooks 61are now disengaged from the pins 68 of the intermediate sections, it ispossible to draw the entire key section assembly forwardly, as a unit,out of the plane of the drum, as shown in Fig. 1, and out of the tire onsaid drum, the spindle 89 providing support for the assembly when soremoved. The key section assembly may be moved to a suilciently remotepoint to allow plenty of space in front of the drum for subsequentremoval of the tire therefrom.

'Ihe drum, now consisting solely of the intermediate sections, is againdriven in the direction indicated by the arrow in Fig. 9, and the brakeapplied to the brake drum I4 of sleeve I2 by means of hand lever |5, sothat the intermediate sections I9 are collapsed in the mannerhereinbefore described. The tire casing may then be removed from thecollapsed drum. Thereafter the drum is restored to expanded, operativecondition by reversing the collapsing operations described, therebycompleting a cycle of operation.

The invention provides such complete collapse r'- of the drum that tiresare removed therefrom without diiiiculty, the collapsing and expandingof the drum is accomplished by power-operated means, and the otheradvantages set out in the foregoing statement of objects are achieved.

Modification may be resorted to without departing from the spirit of theinvention or the scope of the appended claims.

What is claimed is:

1. Tire building apparatus` comprising a sectional tire building drumhaving key sections movable radially toward the axis of the drum andlaterally out of the operative plane of the drum and intermediatesections movable radially toward the axis of the drum after the' keysections have been moved laterally of the operative plane of the drum,power means for rotating the drum, and means for utilizing said powermeans for effecting radial movement of the key sections and of theintermediate sections.

2. Tire building apparatus comprising a sectional tire building drumhaving a plurality of key sections movable radially toward the axis ofthe drum and laterally out of the operative plane of the drum, said keysections being connected to an axial member that is angularly movablerelatively of the drum to effect collapse of said key sections, powermeans for rotating the drum, and non-rotative means engageable with saidaxial member for tating with the drum.

3. Tire building apparatus comprising a sectional tire building drumhaving a plurality of key sections movable radially toward the axis ofthe drum and laterally out of the operative plane of the drum, said keysections being connected to an axial member that is angularly movablerelatively of the drum to effect collapse of said key sections, powermeans for rotating the drum, and a mobile structure having anon-rotative element engageable with said axial member for preventingthe same from rotating with the drum to effect collapse of the keysections and for supporting the key section assembly when it is movedlaterally out of the plane of the drum.

4. A combination as dei-ined in claim 3 in which the axial member of thekey sections is tubular, and the non-rotative element of the mobilestructure is formed as a spindle adapted to be telepreventing the samefrom roscoped with the tubular axial member for at least a portion ofits length.

,5. A combination as defined in claim 3 in which the axial member of thekey sections is tubular and is formed at its outer end with a polygonalsocket, and the non-rotative element of the mobile structure is aspindle that is formed with a polygonal portion engageable in saidsocket.

6. Tire building apparatus comprising a sectional tire building drumhaving key sections and intermediate sections radially movable in theoperative plane of the drum, a screw at the axis of said drum, a nut onsaid screw, power means for rotating the drum, means for utilizing thesaid power means for effecting relative rotation of the screw and nut soas to move the latter longitudinally of the screw, and bell cranksconnecting said nut to the respective key sections whereby axialmovement of the nut effects radial movement of said sections.

7. Tire building apparatus comprising a sectional tire building drumcomprising radially movable key sections and radially movableintermediate sections, a rotatable spindle supporting and driving saiddrum, a hub connected to the intermediate sections and xed to one regionof said spindle, a tubular sleeve journaled on another region of saidspindle, a portion of said sleeve being exteriorly threaded, a hub forthe key sections journaled on an unthreaded portion of said sleeve, anut on the threaded portion of said sleeve, and means connecting saidnut to said key sections for effecting radial movement of said keysections when the nut is moved relatively of the threaded sleeve.

8. A combination as defined in claim 7 including means for effectingrelative angular movement of the threaded sleeve and driving spindle forcausing axial movement of the nut along the sleeve.

9. Tire building apparatus comprising a power driven spindle, asectional tire building drum mounted thereon, said drum comprisingradially movable intermediate sections and a key section assemblyremovable as a unit out of the operative plane of the drum, a sleevesurrounding said spindle and movable angularly relatively thereto, aring gear on said sleeve, gear means connecting said ring gear to therespective intermediate sections for effecting radial movement of thelatter, and means for retarding angular movement of the ring gear andsleeve while the spindle continues to rotate.

10. A combination as defined in claim 9 including radially disposedguide means carried by the respective intermediate sections, said guidemeans being engageable with the drinn-spindle for limiting thecollapsing movement of the sections.

l1. Tire building apparatus comprising a power driven spindle, asectional tire building drum mounted thereon, said drum comprisingradially movable intermediate sections and a key section assemblyremovable as a unit out oi the operative plane oi the drum, means foreffecting radial movement of the intermediate sections when the keysections are removed, a hub for said intermediate sections mounted onsaid spindle, radial guide rods carried by the respective intermediatesections extending through overhanging portions of the hub and adaptedto engage said spindle to limit the collapsing movement of saidsections, and means on the inner ends oi said guide rods engageable withthe hub structure for limiting the outward movement of the guide rods asa means for determining the expanded, operative position of theintermediate sections.

12. A combination as deiined in claim 11 in which the last mentionedmeans is adjustable for varying the effective length of the guide rods.

13. Tire building apparatus comprising a power driven spindle, asectional tire building drum mounted thereon, said drum comprisingradially movable intermediate sections and a key section assemblymovable out of the operative plane of the drum, a hub on said spindle,radially disposed guide rods xed to the respective intermediate sectionsand slidably mounted in said hub, a sleeve surrounding said spindle andmovable angularly relativelyv thereto, brake means engageable with saidsleeve for retarding rotation thereof relatively of the spindle, a ringgear fixed on said sleeve, respective racks connected to saidintermediate sections, and gear means between said racks and said ringgear for effecting radial movement of the intermediate sections when therotation of the ring gear and sleeve is retarded with relation to therotation of the spindle.

14. Tire building apparatus comprising a sectional tire building drumcomprising a key section assembly removable as a unit out of theoperative plane of the drum when in collapsed condition, said unitincluding a member adapted to collapse the key sections upon relativerotative movement of the member and the drum, and means engageable withsaid member for effecting said relative rotary movement, said meansincluding a member designed to fracture under excessive strain.

ALLEN L. HESTCN.

